Feeding mechanism for fibrous layers



Jan. l2, 1937. sc w -i I 2,067,350

FEEDING MECHANISM FOR FIBROUS LAYERS Filed July :51, 1955 Patented Jan. 12, 1937 UNITED STATES PATENT OFFICE FEEDING MECHANISM FOR FIBROUS LAYERS poration of Delaware Application July 31, 1935, Serial No. 33,924

1 Claim.

The mechanism of the present invention is designed particularly for use in the manufacture of layers of distended fibrous material of the character set forth and described in the Bryant 5 Patent No. 1,740,280, issued December 17, 1929. This material consists of a mass of cellulose fibers which have been distended by the use of a liquid solution including a foaming agent such as saponin, which upon agitation produces a foam of minute bubbles which serve to distend the fibers in the production of a loose fiuffy mass, which is thereafter fed in the form of a thin mix upon the wire of a Fourdrinier machine and carried forward as a relatively thick layer of slight tensile strength.

The liquid is in part drained from the material as it advances upon the wire of the Fourdrinier machine and is subjected to suction, after which the layer is continuously advanced into an 20 elongated oven, through which it passes and is finally dried in preparation for cutting into sections of the required length for use as insulating material, hygienic pads, hospital supplies or the like, depending upon the character and grade of the fiber and the details of the treatment to which it is subjected. The process in general is that set forth in the Bryant Patent No. 1,841,- 785, issued January 19, 1932.

In feeding forward the continuous unbroken layer of fibrous material, difficulty has heretofore been experienced in effecting a transfer of the materialfrom the wire of the Fourdrinier machine to the endless feeding belt or apron whereon it is carried through the oven for the final drying operation. This difficulty has been due to the fact that the layer of material is relatively thick and fragile, having little tensile strength and being incapable of contact by pressure rolls or like feeding agencies, which if used 40 would compact the layer and thus destroy its usefulness for the purpose intended. The problem involved is that of lifting or separating the layer from contact with the Fourdrinier wire and transporting it across a gap to the belt or apron of the oven without in any way disturbing its forward advance or otherwise tearing, abrading or disturbing the relatively fragile layer, which prior to complete drying is in a relatively soft or mushy condition.

50 The present invention comprises a transfer belt and the use of an air blast to effect a slight lifting of the layer at the points of transfer, so that it will be elevated sufficiently by air pressure at these points to span the gaps in the feeding mechanism withoutsagging down and bending or wrinkling at the points where it is not feasible to provide positive mechanical support.

Further objects and details will appear from a description of the invention in conjunction with the accompanying drawing, wherein,

Figure 1 is a side elevation showing at the left the terminus of a Fourdrinier machine, and at the right the inlet end of the oven, with the transfer mechanism of the present invention occupying an intermediate position;

Fig. 2 is a sectional elevation of the transfer mechanism and associated parts; and

Fig. 3 is a detail plan view of the transfer screen and rollers.

The layer of distended fibrous material is carried forward upon the endless wire I of a Fourdrinier machine, and is confined between deckle strips H of the character commonly employed in paper making operations. The wire I!) at the discharge end passes over a roller 12 which is suitably driven by a belt I3 which is carried around a driving pulley I4 rotated by a power belt l5 leading to a suitable source of power.

The layer of material upon the Fourdrinier wire passes over vacuum boxes I6 and I1, which serve to extract a certain percentage of the moisture from the layer and at the same time have the effect of compacting the surface fibers in contact with the wire to a suflicient extent to form thereon a paperlike skin which affords increased tensile strength and a somewhat tough surface to the layer, although it is not the intention in all cases to apply sufficient suction to form the surface skin, since in some cases it may be desirable to produce a softer and more fluffy layer for hospital use or in the formation of bandages, pads or the like. These features of operation are set forth and described in the Bryant Patent No. 1,841,785, and need not be elaborated in detail.

It suffices to state, however, that the transfer mechanism of the present invention is designed to act upon a layer irrespective of the presence or absence of a skin which may increase its tensile strength somewhat, since in all cases the layer at the point of transfer will be relatively soft, thick and fragile.

The upper turn of the Fourdrinier wire affords a horizontal surface which is aligned with the surface of a feeding belt or apron I8 extending outwardly from the intake end of an oven 19 and passing around the roller 20, which is one of a series which serve to feed forward the upper turn of the apron in order to carry the material for a considerable distance through an elongated oven,

of the general character shown and described in the Bryant Patent No. 1,841,785.

It is necessary, in the feeding of the Fourdrinier wire and the feeding of the apron, that these two feeding agencies be carried around rollers of relatively large diameter and at a uniform rate of surface travel, which is imparted by a suitable train of power transmission mechanisms, which method of feeding results in the formation of a gap across which the fragile layer must be transported without interference and without compression or the like.

It is also necessary, at the terminus of the Fourdrinier wire, to strip the layer from the surface of the wire into which it becomes more or less enmeshed by reason of its initial fluidity and the employment of suction in the extraction of the moisture. In short, the material toward the terminus of the wire has a tendency to stick or adhere to the surface, so that it has been found difiicult to feed it satisfactorily across a fixed shoe or bridge without danger of disturbing the surface or tearing the layer at the point of transfer.

In order to overcome the difliculties above noted, the roller I2 around which the Fourdrinier wire passes is provided with apertures or perforations 2i in its surface, which give it a foraminous or perforate character, and the shell of the roller is contacted on its inner side by an elongated slotted nozzle 22, which consists of converging plates 23 enclosing a pressure chamber 24, the 'plates converging to a narrow aperture 25 and contacting the inner surface of the shell, so that a blast of air will be discharged at the point 26 and against the under-surface of the layer A at a point slightly beyond the point where the layer lies tangent to the surface of the roller. The emission of an air blast at this point serves to strip the layer from the Fourdrinier wire and suspend it in elevated relation across the gap between the wire and the transfer screen 21.

The transfer screen is of endless formation and carried around two upper rollers 28 and 29 and a lower tension roller 30, and as shown the roller 29 is power driven by a belt 3|, and the roller 28 is also power driven through a transmission belt ,32. The belt 3| passes around a pulley 33 on a shaft 34 carrying a driven pinion 35 which meshes with a driving pinion 36 on a shaft 3'! carrying a roller 38 driven by a belt 39 passing around a roller 40 on a shaft 4! carrying a gear 42 which meshes with a gear 43 on the shaft 44 which is driven through the power belt l5.

The roller 29 has a shell of foraminous or perforate formation, being provided with apertures .45, and within the roller is an air pressure pipe Mi having a slot or nozzle 4i registering with the perforations 45, so that a blast of air will be discharged obliquely upward against the under surface of the layer at the point of its delivery by the transfer apron, thereby suspending and sustaining the layer in passing across the gap and until it is supported upon the belt or apron leading through the drying oven.

In operation, the material advancing upon the Fourdrinier wire will be progressively drained as .it approaches the discharge end of the wire, and as the layer reaches the point where the wire turns downwardly around the periphery of the roller 42, it will be subjected to a lifting or stripping action by the blast of air at the point 26, which exerts sufficient pressure to maintain it in a substantially level condition Without contact with mechanical strippers or similar elements which might have the effect of tearing or abrading the layer.

The upper turn of the transfer screen lies in the same level plane with the Wire, so that the layer, after passing the first gap, will be supported upon and fed forwardly by the screen at a uniform rate of surface travel, and at the terminus of the transfer feeding it will be elevated from the screen by the air pressure discharge through the apertures in the roller 29 and buoyed up until it again receives the support afforded by the belt or apron advancing through the oven, which also occupies the same surface level and is advanced at a speed which is uniform with the feeding speed of the Fourdrinier wire and the transfer apron. As the layer progresses through the oven, it will become thoroughly dried and sufficiently coherent to permit its severance and removal at the discharge end of the oven.

The mechanism of the present invention enables the operations to be performed continuously and without any break or interruption in the continuity of the feeding operation, and without any disturbance which might tend to impair the uniformity of the product to subject it to distortion, tearing or abrasion at a period in its progress at which it is relatively damp and fragile and incapable of withstanding any degree of severe manipulation.

Although the invention has been described with particularity as to detail, itis not the intention to limit the same to the mechanism shown, since modifications thereof may be made Without departing from the spirit of the invention.

Furthermore, although the transfer mechanism of the present invention is employed for transporting the layer from the wire of a Fourdrinier machine to the apron of a drying oven, such mechanism might be otherwise employed for transporting purposes, so that it is not the intention, unless otherwise indicated in the claim, to limit the use of the transfer mechanism to the particular series of operations hereinbefore described in detail.

I claim:

the perforations in the roller and against the under surface of the layer carried thereby at a point contiguous to the line of tangential contact between the wire and the roller to strip the layer therefrom and prevent it-from being carried around the turn of the roller, a second roller in spaced relation to the first mentioned roller and having an endless feeding apron carried thereby in flush alignment with the feeding surface of the Fourdrinier wire, an oven into which the endless feeding apron is mounted to travel, transfer mechanism within the downwardly convergent gap between the upper turns of the rollers, said mechanism comprising an endless screen and rollers of relatively small diameter located respectively in closely adjacent relation to the Fourdrinier wire and the apron for holding the upper turn of the screen in closely aligned flush rela tion with the wire and the apron respectively, the

, roller at the discharge end of the transfer mechanlsm having a perforated shell and an air discharge nozzle located within the shell and adapted to discharge air through the perforations in the roller and against the under surface of the layer to strip the layer therefrom and suspend it in substantially level relation during its advance to the apron, and means for feeding the Fourdrinier wire. the apron and the transfer screen at a uniform rate of surface travel to carry the layer from the Fourdrinier wire and into the oven in a substantially straight line movement of advance.

SIDNEY L. SCHWARZ. 

